I am assuming that you are a fresher, so if you are planning to begin your career in Data Science, then you need to clear your basic fundamentals first. You should have good knowledge of a programming language. Most preferable is python. You must have the knowledge of list, NumPy, data frame operations. As these modules are the core to perform any operations.
If you are good in these concepts then you can move to the data visualization part. How to create visuals for your data sets and all. As a beginner, you can start your journey by learning these concepts. But there is a long way to become a data scientist. I have attached one blog link below. You can go through that for more details.